Possibly bad seals on the filter. Had one earlier this year that would do the same. Changed the filter for a Bosch model and the problem went away.
I replaced my fuel filter/regulator with a new one from Bosch, and the little rubber fuel injection hoses connected to it.
After I cycled ignition like 5 times to build fuel pressure it started to make this sound.
Struggled a bit after starting it but after 20 seconds settled and it now drives good.
Car feels solid no lack of power or nothing.
I dare to say it even drives better than before.
I do the air filter every second service (12k) and the fuel filter every 18k, or third service.
the inlet side of the filter being completely gunked with black varnish.
Start by replacing the ancient NAPA fuel filter, and only use a Bosch version.
I’m on my 2nd fuel filter this week, was getting a bit of black smoke out of the exhaust so dumped injector cleaner directly into the old one and revved the stones off it . Big clouds of black smoke! Then changed the fuel filter for a fresh Bosch one and exhaust is back to normal now.
VDO is OE and can be got for €120~. Get a fuel filter for €15 from Bosch, part of your maintenance anyway.
Recently, (about 2 weeks ago) I did a new fuel filter, new spark plugs, new plug wires, new distributor rotor and cap.
Bosch is not as good as it used to be because they want to get into the DIY market. As far as their fuel filters, I do not think you will go wrong.
New Bosch fuel filter: A trick I've done on other cars, is opposed to running endless wiring looms up into the rain tray, across to the ecu box (the into the cab entry point) which pop into the OEM rats nest above the pedals is find the sweet spot from the fenders into the cab.
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